At present, most of hair dyeing products available from markets are oxidative hair dyeing products comprising thioglycolic acid as a penetration enhancing agent, aromatic amines such as p-phenylenediamine as a dye and hydrogen peroxide as an oxidant. Many studies and reports demonstrate that thioglycolic acid, p-phenylenediamine, hydrogen peroxide and the like all have certain toxicities and allergies. Hence, the development of hair dyeing products with a high safety is paid more and more attention. In recent years, many natural hair dyeing products are available from markets, but such products usually have the following two drawbacks: one is that some of so-called “purely natural” or “organic” hair dyeing products merely are added with some vegetative concept components, but still comprise harmful chemical substances such as p-phenylenediamine, so that long-term use thereof still produces relatively severe side-effects; and the other is that natural hair dyeing components usually are larger molecules so that it is difficult to dye and maintain the color permanently, and thus the hair dyeing effects, the stability of the products and convenience of application are still not satisfactory. In addition, it has been found that for some natural hair dyeing products such as those disclosed in CN1401310A (Chinese Patent Application No. 01127328.3, publication date) and CN1593375A (Chinese Patent Application No. 200410009258.4, publication date of 2005 Mar. 16), after being prepared and used according to the method disclosed therein, their hair dyeing effects, especially the effects of darkening white hairs are relatively poor, and the stability of their mordant components is not good, so that the final product contains relatively lower concentration of free iron ions which influences the hair dyeing effects of the products, specifically during their shelf life of the products. In addition, these products all need multiple hair washings and multiple applications before and during the hair dyeing procedures, which is less convenient for use. Therefore, there is still a need for developing purely natural hair dyeing products with good safety, coloring effects, stability and convenience.